CN110834385B - Cutting device - Google Patents

Abstract

Provided is a cutting device capable of producing a device chip of good quality. The cutting device includes a machining feed direction determination means. The machining feed direction determination means includes: a photographing unit photographing an area including the cutting groove; and a recording unit that records the shot chipping data of the cutting groove. The recording unit records: first chipping data of a cutting groove obtained by cutting a workpiece from a first direction; second chipping data of a cutting groove obtained by cutting the workpiece from a direction opposite to the first direction; third edge breakage data of a cutting groove obtained by cutting the workpiece from a second direction perpendicular to the first direction; and fourth chipping data of a cutting groove obtained by cutting the workpiece from a direction opposite to the second direction.

Description

cutting device

technical field

The present invention relates to a cutting device which cuts a workpiece with a high-speed rotating cutting tool.

Background technique

The wafer is divided by a plurality of intersecting dividing lines, and a plurality of devices such as IC and LSI are formed on the front surface. Device chips, each device chip obtained by dividing is used in electronic devices such as mobile phones and personal computers.

The cutting device has: a chuck table having a holding surface for holding a workpiece; a cutting unit having a rotatable cutting tool for cutting the workpiece held by the chuck table; a cutting water supply mechanism, which supplies cutting water to the cutting tool and the workpiece; a machining feed mechanism, which performs machining feeding of the chuck table and the cutting unit in an X-axis direction parallel to the holding surface; and index feeding mechanism, which index-feeds the chuck table and the cutting unit in the Y-axis direction parallel to the holding surface and perpendicular to the X-axis direction, and the cutting device can cut the wafer with high precision (for example, refer to Patent Document 1).

Patent Document 1: Japanese Patent Laid-Open No. 2005-46979

However, there is a problem that the size and number of chipping generated on the device chip may vary depending on the relative processing feeding direction of the cutting unit and the chuck table, resulting in a difference in the quality of the device chip.

Contents of the invention

Therefore, an object of the present invention is to provide a cutting device capable of producing high-quality device chips.

According to the present invention, a cutting device is provided, wherein the cutting device includes: a chuck table having a holding surface for holding a workpiece; a cutting unit having a cutting unit for cutting the workpiece held by the chuck table. The cutting tool and the cutting tool can be rotated; the cutting water supply mechanism, which provides cutting water to the cutting tool and the workpiece; the processing feed mechanism, which makes the chuck table and the cutting unit parallel to the holding surface The processing feed is carried out relatively in the direction of the X-axis; the index feed mechanism, which performs relative processing of the chuck table and the cutting unit in the direction of the Y-axis parallel to the holding surface and perpendicular to the X-axis direction indexing feed; and a processing feed direction judging mechanism, the processing feed direction judging mechanism includes: a photographing unit, which photographs the area containing the cutting groove; and a recording unit, which records the chipping data of the photographed cutting groove Recording is carried out, and the recording unit is recorded with: the first chipping data of the cutting groove obtained by cutting the workpiece from the first direction; The second chipping data of the cutting groove; the third chipping data of the cutting groove obtained by cutting the workpiece from the second direction intersecting with the first direction; and the third chipping data of the cutting groove from the direction opposite to the second direction The fourth chipping data of the cutting groove obtained by cutting the workpiece.

Preferably, the photographing unit photographs the cutting groove formed on the back surface of the workpiece by transmitting light of a wavelength of the workpiece, and the recording unit records: First back chipping data on the back side of the cutting groove; second back chipping data on the back side of the cutting groove obtained by cutting the workpiece from a direction opposite to the first direction; Third back chipping data on the back side of the cut groove obtained by cutting the workpiece in the second direction perpendicular to the second direction; and the back surface of the cut groove obtained by cutting the workpiece in a direction opposite to the second direction Edge chipping data on the fourth back of the side. Preferably, the processing feed judging mechanism has a judging unit, and the judging unit performs the first edge chipping data, the second edge chipping data, the third edge chipping data and the fourth edge chipping data recorded in the recording unit. Compare to determine the direction in which the cutting groove is formed.

Preferably, the processing feed judging mechanism has a judging unit, and the judging unit not only checks the first edge chipping data, the second edge chipping data, the third edge chipping data, and the fourth edge chipping data recorded in the recording unit For comparison, also compare the first backside chipping data, the second backside chipping data, the third backside chipping data and the fourth backside chipping data recorded in the recording unit, so as to determine the formation of cutting The direction of the slot. Preferably, the processing feed determination means includes at least one of a display unit that displays the chipping data or an output unit that outputs the chipping data. Preferably, the chipping data includes the size and quantity of chipping. Preferably, the edge chipping data includes an image.

According to the present invention, the direction in which the cutting groove is formed can be determined by comparing the first to fourth chipping data, and the wafer can be cut from an appropriate direction to produce a high-quality device chip.

Description of drawings

Figure 1 is a perspective view of a cutting device constructed in accordance with the present invention.

Fig. 2 is an enlarged perspective view of the cutting unit shown in Fig. 1 .

3( a ) is a plan view of a wafer formed with cutting grooves cut from the first direction, and FIG. 3( b ) is an enlarged view of part A in FIG. 3( a ).

(a) of Fig. 4 is a top view of a wafer in which cutting grooves obtained by cutting from a direction opposite to the first direction are further formed on the wafer shown in (a) of Fig. 3 , and (b) of Fig. 4 is a plan view of Enlarged view of part B in (a) of 4.

(a) of Fig. 5 is a top view of a wafer in which cutting grooves obtained by cutting from a second direction perpendicular to the first direction are further formed on the wafer shown in (a) of Fig. 4 , and (b) of Fig. 5 It is an enlarged view of part C in (a) of FIG. 5 .

(a) of Fig. 6 is a top view of a wafer in which cutting grooves obtained by cutting from a direction opposite to the second direction are further formed on the wafer shown in (a) of Fig. 5 , and (b) of Fig. 6 is a plan view of Enlarged view of part D in (a) of 6.

FIG. 7 is a graph showing an example of chipping data output by an output unit.

Label description

2: cutting device; 4: chuck table; 6: cutting unit; 8: cutting water supply mechanism; 22: cutting tool; 28: photographing unit; 38: display unit.

Detailed ways

Hereinafter, preferred embodiments of the cutting device according to the present invention will be described with reference to the drawings.

The cutting device 2 shown in FIG. 1 has: a chuck table 4 that has a holding surface for holding a workpiece; a cutting unit 6 that has a workpiece held by the chuck table 4 in a rotatable manner. The cutting tool for cutting the object; the cutting water supply mechanism 8, which provides cutting water to the cutting tool and the workpiece; the processing feed mechanism (not shown), which connects the chuck table 4 and the cutting unit 6 to the holding surface On the parallel X-axis direction (the direction shown by the arrow X in Fig. 1), the processing feed is relatively carried out; the indexing feed mechanism (not shown), which places the chuck table 4 and the cutting unit 6 on the holding surface Relatively indexed feeding is performed in the Y-axis direction (the direction indicated by arrow Y in FIG. 1 ) parallel to and perpendicular to the X-axis direction; and a processing feed direction determination mechanism. In addition, the plane defined by the X-axis direction and the Y-axis direction is substantially horizontal.

The chuck table 4 includes a chuck table 12 , which is rotatably attached to the device case 10 so as to be able to move in the X-axis direction. The chuck table 12 is rotated around an axis extending in the vertical direction by a chuck table motor (not shown) built in the device case 10 . A porous circular suction chuck 14 connected to a suction unit (not shown) is disposed on the upper end portion of the chuck table 12 . In addition, in the chuck table 12 , suction means is used to generate suction force on the suction chuck 14 , thereby suctioning and holding the workpiece placed on the upper surface. Thus, in the present embodiment, the holding surface for holding the workpiece is constituted by the upper surface of the suction chuck 14 . In addition, a plurality of jigs 16 are arranged at intervals in the circumferential direction on the periphery of the chuck table 12 .

1 and FIG. 2, the cutting unit 6 includes: a main shaft housing 18, which is supported on the device housing 10 in a manner that can be lifted and moved freely in the Y-axis direction; a main shaft 20, which can move the Y-axis The direction is supported on the main shaft housing 18 so as to rotate as the axis; the cutting tool 22 is fixed on the front end of the main shaft 20; and a tool cover 24 mounted on the front end of the spindle housing 18.

As shown in FIG. 2 , the cutting water supply mechanism 8 includes a cutting water supply nozzle 26 attached to the cutter cover 24 . The cutting water supply nozzles 26 extending along the side surfaces of the cutting insert 22 are provided as a pair on both sides of the cutting insert 22 , but only the cutting water supply nozzle 26 on one side is shown in FIG. 2 . The cutting water supply nozzle 26 is connected to a cutting water supply source (not shown), and when cutting the workpiece held by the chuck table 12 with the cutting tool 22, the cutting water supplied from the cutting water supply source is A plurality of injection ports (not shown) of the cutting water supply nozzle 26 are injected toward the cutting tool 22 and the workpiece.

The machining feed mechanism of this embodiment includes: a ball screw (not shown) connected to the chuck table 12 and extending in the X-axis direction; and a motor (not shown) that rotates the ball screw, This machining feeding mechanism performs machining feeding of the chuck table 12 relative to the cutting unit 6 in the X-axis direction.

The index feed mechanism of this embodiment includes: a ball screw (not shown) connected to the spindle housing 18 and extending in the Y-axis direction; and a motor (not shown) that rotates the ball screw, This index feed mechanism index-feeds the spindle housing 18 relative to the chuck table 4 in the Y-axis direction. In addition, the main shaft housing 18 is plunged and fed (raised and lowered) in the vertical direction by a plunge and feed unit having a ball screw (not shown) extending in the vertical direction and a mechanism for rotating the ball screw. motor (not shown).

The machining feed direction determination mechanism includes an imaging unit 28 that captures an image of a region including a cutting groove formed on the workpiece by the cutting tool 22 . The photographing unit 28 disposed above the chuck table 12 has: a common photographing element (CCD), which photographs the workpiece through visible light; an infrared ray irradiation unit, which irradiates light of a wavelength that passes through the workpiece; An optical system that captures infrared rays irradiated by the infrared irradiating unit; and an imaging element (infrared CCD) that outputs electrical signals corresponding to the infrared rays captured by the optical system (both are not shown).

As shown in FIG. 1 , a control unit 30 for controlling the operation of the cutting device 2 is electrically connected to the imaging unit 28 . The control unit 30 is composed of a computer, and has: a central processing unit (CPU) 32, which performs calculation processing according to a control program; a read-only memory (ROM) 34, which stores the control program, etc.; The memory (RAM) 36 stores calculation results and the like.

The random access memory 36 of the control unit 30 functions as a recording unit that records chipping data of the cutting groove (data of defects generated on both sides of the cutting groove) captured by the imaging unit 28 . In addition, in the read-only memory 34 of the control unit 30 is stored a control program that functions as a judging unit that determines the direction in which cutting grooves are to be formed on the workpiece based on chipping data recorded in the random access memory 36. and a control program that functions as an output unit that outputs the edge collapse data recorded in the random access memory 36, and the like. In addition, a display unit 38 for displaying edge chipping data recorded in the random access memory 36 is electrically connected to the control unit 30 .

In this way, in addition to the imaging unit 28 and the recording unit (random access memory 36), the machining feed judging mechanism of the present embodiment includes a judging unit that determines whether the edge chipping of the workpiece is performed based on the edge chipping data recorded in the recording unit. The direction in which the cutting groove is formed on; the display unit 38, which displays the chipping data; and the output unit, which outputs the chipping data.

Here, the workpiece processed by the cutting device 2 will be described. Also shown in FIGS. 1 and 2 is a disk-shaped wafer 40 as a workpiece. As shown in FIG. 2 , the front surface 40 a of the wafer 40 is divided into a plurality of rectangular areas by grid-like dividing lines 42 , and devices 44 such as ICs and LSIs are respectively formed in the plurality of rectangular areas. In addition, an orientation flat 46 indicating crystal orientation is formed on the periphery of the wafer 40 . In addition, in this embodiment, the back surface 40b of the wafer 40 is attached to the adhesive tape 50 whose peripheral edge is fixed to the ring frame 48, but the front surface 40a of the wafer 40 may be attached to the adhesive tape 50.

The description of the cutting device 2 will continue with reference to FIG. 1 . On the device case 10 of the cutting device 2 , a cassette 52 containing a plurality of wafers 40 supported by an annular frame 48 via an adhesive tape 50 is placed on a cassette mounting table 54 which can be moved up and down. The cartridge mounting table 54 is raised and lowered by a lifting unit (not shown) having a ball screw and a motor. In addition, the cutting device 2 further includes: a loading and unloading unit 58 that pulls out the wafer 40 before cutting from the cassette 52 and carries it out to the temporary storage table 56, and places the chipped wafer 40 positioned on the temporary storage table 56 Carried into the box 52; the first transfer mechanism 60, which will be carried out from the box 52 to the wafer 40 before cutting of the temporarily placed workbench 56 to the chuck workbench 12; cleaning; and the second transfer mechanism 64 , which transfers the chipped wafer 40 from the chuck table 12 to the cleaning unit 62 .

When using the cutting device 2 to divide the wafer 40 into individual device chips for each device 44, firstly, the wafer 40 is sucked and held by the upper surface of the chuck table 12 with the front surface 40a of the wafer 40 facing upward, and a plurality of chucks are used to hold the wafer 40. 16 is fixed to the ring frame 48. Next, the wafer 40 is photographed from above by the photographing unit 28, and the planned dividing line 42 is aligned with the X-axis direction based on the image of the wafer 40 photographed by the photographing unit 28, and the cutting tool 22 is positioned in the same position as the X-axis direction. Above the planned dividing line 42 . Next, the cutting tool 22 is rotated together with the spindle 20 by a motor.

Next, as shown in FIG. 2 , the spindle housing 18 is lowered so that the edge of the cutting tool 22 cuts in from the front surface 40 a of the wafer 40 until it reaches the back surface 40 b on the planned division line 42 coincident with the X-axis direction, and the chuck The table 12 performs machining feed in the X-axis direction relative to the cutting unit 6 , and performs cutting machining to form the cutting groove 66 along the planned dividing line 42 . Then, according to the Y-axis direction interval of the dividing line 42, while the cutting unit 6 is indexed and fed relative to the chuck table 12 in the Y-axis direction, the cutting process is repeated, and all the divisions consistent with the X-axis direction are repeated. A cutting groove 66 is formed on the predetermined line 42 . Next, after rotating the chuck table 12 by 90 degrees, the cutting process is repeated while performing index feeding, and cutting is also formed on all the planned dividing lines 42 perpendicular to the planned dividing lines 42 on which the cutting grooves 66 were previously formed. Slot 66. In this way, the wafer 40 is divided into individual device chips for each device 44 .

In the cutting device 2 of the present embodiment, before performing the above-mentioned cutting process, the following test process is performed to determine an appropriate direction for forming the cutting groove 66, thereby producing a high-quality device chip with less chipping.

In the test process, firstly, the first edge chipping data of the cutting groove obtained by cutting the wafer 40 from the first direction is recorded in the recording unit. In this embodiment, the orientation flat 46 is positioned on the lower side in FIG. 3 , and the wafer 40 is cut from the left side toward the right side in FIG. 3 to form the cutting groove 66 a. Next, the area including the cutting groove 66a formed on the front surface 40a of the wafer 40 is photographed by the imaging unit 28, and the captured image is analyzed, and the chipping data (first chipping data) of the chipping groove 66a is shown in FIG. 7 It is recorded as shown in the random access memory 36 as a recording unit. An example of chipping that occurs when forming the cutting groove 66a is shown by reference numeral 68a in FIG. 3(b).

The chipping data recorded in the recording unit includes the size and quantity of chipping. When recording chipping data in the recording unit, for example, the number of chipping can be recorded according to size of chipping such as less than 5 μm, 5 μm or more, less than 10 μm, or 10 μm or more. The number of chipping may be measured in a predetermined length (for example, 1 cm), or the number of chipping may be measured along the entire length of the cutting flute. In addition, an image of a region including a cutting groove may be recorded in the recording unit as chipping data.

After recording the first chipping data, the second chipping data of the cutting groove obtained by cutting the wafer 40 from the direction opposite to the first direction is recorded in the recording unit. In this embodiment, the wafer 40 is rotated 180 degrees from the position shown in FIG. The wafer 40 is cut toward the right side to form the cutting groove 66b. Next, the area including the cutting groove 66b formed on the front surface 40a of the wafer 40 is photographed by the imaging unit 28, and the edge chipping data (second edge chipping data) of the imaged cutting groove 66b is recorded in the in the recording unit. In this embodiment, as shown in FIG. 4( b ), chipping does not occur when the cutting groove 66 b is formed.

After recording the second chipping data, the third chipping data of the cutting groove obtained by cutting the wafer 40 from the second direction intersecting the first direction is recorded in the recording unit. In this embodiment, the wafer 40 is rotated 90 degrees counterclockwise from the position shown in FIG. 5(a) cuts the wafer 40 from the left side to the right side to form the cutting groove 66c. Next, the area including the cutting groove 66c formed on the front surface 40a of the wafer 40 is photographed by the imaging unit 28, and the edge chipping data (third edge chipping data) of the imaged cutting groove 66c is recorded in the in the recording unit. An example of chipping generated when forming the cutting groove 66c is shown by reference numeral 68c in FIG. 5(b).

After recording the third chipping data, the fourth chipping data of the cutting groove obtained by cutting the wafer 40 from the direction opposite to the second direction is recorded in the recording unit. In this embodiment, the wafer 40 is rotated 90 degrees clockwise from the position shown in FIG. 6(a) cuts the wafer 40 from the left side toward the right side to form the cutting groove 66d. Next, the area including the cutting groove 66d formed on the front surface 40a of the wafer 40 is photographed by the imaging unit 28, and the edge chipping data (fourth edge chipping data) of the imaged cutting groove 66d is recorded in the in the recording unit. In the present embodiment, as shown in FIG. 6( b ), chipping did not occur when the cutting groove 66 d was formed.

After the first to fourth chipping data are recorded, the direction in which cutting grooves are to be formed in the cutting process is determined by comparing the first to fourth chipping data recorded in the recording unit. The determination of the formation direction of the cutting groove is performed by the determination means of the cutting device 2 in this embodiment, but it may be performed by an operator. The operator displays the first to fourth edge chipping data on the display unit 38, or outputs (prints, etc.) the first to fourth edge chipping data in the form of a graph as shown in FIG. The direction in which the groove is formed.

Determination of the formation direction of the cutting groove in this embodiment will be described. First, the first edge chipping data of the cutting groove 66a obtained by cutting the wafer 40 from the first direction and the wafer 40 from the direction opposite to the first direction will be described. When comparing the second edge chipping data of the cutting groove 66b obtained by cutting at 40, edge chipping occurs on both sides of the cutting groove 66a, but no edge chipping occurs on both sides of the cutting groove 66b. direction, the direction opposite to the first direction is determined as the formation direction of the cutting groove.

In addition, regarding the direction perpendicular to the orientation plane 46, the third edge chipping data obtained by cutting the wafer 40 from the second direction and the third chipping data obtained by cutting the wafer 40 from the direction opposite to the second direction When comparing the fourth edge chipping data of the cutting groove 66d, edge chipping occurs on both sides of the cutting groove 66c, and edge chipping does not occur on both sides of the cutting groove 66d, so the direction opposite to the second direction is determined as the cutting groove direction of formation.

When comparing edge chipping data, the direction in which the number of chipping is small is basically determined as the direction in which the cutting groove is formed. However, from the viewpoint of the impact on the bending strength of the device chip, etc. When the number is large, the direction in which chipping with a small size is formed is determined as the direction in which the cutting groove is formed. For example, when five chippings of less than 5 μm are formed in the first direction and three chippings of 10 μm or more are formed in the direction opposite to the first direction, the first direction is determined as the formation direction of the cutting groove.

As described above, in the cutting device 2 of the present embodiment, the direction in which the cutting grooves are formed can be specified by comparing the first to fourth chipping data, so the wafer 40 can be cut from an appropriate direction with less chipping. Good quality device chips.

In addition, in this embodiment, the first to fourth edge chipping data are recorded in the recording unit by imaging each area including the cutting grooves 66a to 66d formed on the front surface 40a of the wafer 40 by the imaging unit 28. In addition to such edge chipping data on the front side 40 a side, back side chipping data on the back side 40 b side of the wafer 40 may be recorded in the recording unit.

Specifically, it is also possible to align the focus of the imaging unit 28 on the back surface 40b of the wafer 40 facing downward, and use the imaging unit 28 to focus on the back surface 40b of the wafer 40 by light of a wavelength that passes through the wafer 40 (for example, infrared rays). Each region of the cutting grooves 66a to 66d is photographed, and the first backside chipping data on the backside 40b side of the cutting groove 66a, the second backside chipping data on the backside 40b side of the cutting groove 66b, and the data on the backside 40b side of the cutting groove 66c are captured. The third back chipping data and the fourth back chipping data on the back side 40b side of the cutting groove 66d are recorded in the recording unit. Furthermore, in addition to the first to fourth chipping data on the front side 40a side of the wafer 40, the first to fourth chipping data on the back side 40b side of the wafer 40 may be compared to determine the direction in which the cutting groove is formed.

In addition, it is preferable that the imaging unit 28 is also used as an imaging unit used in an alignment unit that detects a region to be cut before cutting the wafer 40 .

Claims (5)

1. A cutting device wherein, The cutting unit has: a chuck table having a holding surface for holding the workpiece; a cutting unit having a cutting tool for cutting the workpiece held by the chuck table and the cutting tool is rotatable; a cutting water supply mechanism that supplies cutting water to the cutting tool and the workpiece; a processing feeding mechanism, which relatively performs processing feeding of the chuck table and the cutting unit in the X-axis direction parallel to the holding surface; an index feed mechanism, which relatively performs index feed of the chuck table and the cutting unit in a Y-axis direction parallel to the holding surface and perpendicular to the X-axis direction; and Machining feed direction judging mechanism, The mechanism for judging the processing feed direction includes: a photographing unit, which photographs the area containing the cutting groove; a recording unit, which records the chipped edge data of the cutting groove; and judging unit, The avalanche data includes the number of avalanches of various avalanche sizes, In this logging unit it is recorded that: The first edge chipping data of the cutting groove obtained by cutting the workpiece from the first direction; Second chipping data of cutting grooves obtained by cutting the workpiece from a direction opposite to the first direction; third chipping data of cutting grooves obtained by cutting the workpiece from a second direction intersecting the first direction; and The fourth chipping data of the cutting groove obtained by cutting the workpiece from the direction opposite to the second direction, The judging unit compares the first edge collapse data, the second edge collapse data, the third edge collapse data and the fourth edge collapse data recorded in the recording unit, and determines the direction in which the number of edge collapse is small is the formation direction of the cutting grooves, but when the number of chippings is large, the direction in which small chippings are formed is also determined as the forming direction of the cutting grooves. 2. The cutting device of claim 1, wherein: The photographing unit photographs the back surface of the workpiece having the cut grooves formed on the front surface by light of a wavelength that transmits the workpiece, In this logging unit it is recorded that: First back chipping data on the back side of the cutting groove obtained by cutting the workpiece from the first direction; Second back chipping data on the back side of the cutting groove obtained by cutting the workpiece from a direction opposite to the first direction; Third back chipping data on the back side of the cutting groove obtained by cutting the workpiece from a second direction perpendicular to the first direction; and The fourth back chipping data on the back side of the cut groove obtained by cutting the workpiece from a direction opposite to the second direction. 3. The cutting device of claim 2, wherein: The judging unit not only compares the first edge avalanche data, the second edge avalanche data, the third edge avalanche data and the fourth edge avalanche data recorded in the recording unit, but also compares the data recorded in the recording unit Compare the first backside chipping data, the second backside chipping data, the third backside chipping data and the fourth backside chipping data, so as to determine the direction of forming the cutting groove. 4. The cutting device of claim 1, wherein: The machining feed direction determination means includes at least one of a display unit that displays the chipping data or an output unit that outputs the chipping data. 5. The cutting device of claim 1, wherein: The chipping data includes images.